In India, for example, more than 400 million people live along the highly polluted Ganges River.

FORBES: In China and India, Turbulence and Volatility Are Part Of The Bargain

New York (CNN) -- A dolphin stranded in Brooklyn's highly polluted Gowanus Canal on Friday has died, according to the Riverhead Foundation.

CNN: Rescuers: Dolphin stranded in polluted New York canal dies

For cadmium to be evident in rice grains as well, the soil in which it was grown must have been especially highly polluted, said Jonathan Wong, a Hong Kong biology professor who has studied mainland soil pollution extensively.

WSJ: Cadmium-Tainted Rice Found in Guangzhou

For cadmium to be evident in rice grains as well, the soil in which it was grown must have been especially highly polluted, said Jonathan Wong, a Hong Kong biology professor who has studied soil pollution extensively on the mainland.

WSJ: Cadmium-Tainted Rice Found in Guangzhou

Michigan's Kalamazoo River is polluted by polychlorinated biphenyls (PCBs), highly toxic chemicals banned in the 1970s.

CNN: Pregnant women should follow guidelines on eating fish